| 63 matches found in 28 documents. Search time: 0.002 seconds. |
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Score: 1.00 |
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| | Journal: Plant Cell Citation: V : 12 ( 11 ) P : 2019-32 | | Literature: oryza Field: abstract Doc ID: pub11090206 | | Abstract: Genetic mapping showed that the rice blast avirulence gene AVR-Pita is tightly linked to a telomere on chromosome 3 in the plant pathogenic fungus Magnaporthe grisea .
AVR-Pita corresponds in gene-for-gene fashion to the disease resistance ( R ) gene Pi-ta .
Analysis of spontaneous avr-pita ( - ) mutants indicated that the gene is located in a telomeric 6 . 5-kb BglII restriction fragment .
Cloning and DNA sequencing led to the identification of a candidate gene with features typical of metalloproteases .
This gene is located entirely within the most distal 1 . 5 kb of the chromosome .
When introduced into virulent rice pathogens , the cloned gene specifically confers avirulence toward rice cultivars that contain Pi-ta .
Frequent spontaneous loss of AVR-Pita appears to be the result of its telomeric location .
Diverse mutations in AVR-Pita , including point mutations , insertions , and deletions , permit the fungus to avoid triggering resistance responses mediated by Pi-ta .
A point mutation in the protease consensus sequence abolishes the AVR-Pita avirulence function . | Matching Sentences:
[ Sen. 3, subscore: 1.00 ]: Genetic mapping showed that the rice blast avirulence gene AVR-Pita is tightly linked to a telomere on chromosome 3 in the plant pathogenic fungus Magnaporthe grisea . AVR-Pita corresponds in gene-for-gene fashion to the disease resistance ( R ) gene Pi-ta . Analysis of spontaneous avr-pita ( - ) mutants indicated that the gene is located in a telomeric 6 . 5-kb BglII restriction fragment . Cloning and DNA sequencing led to the identification of a candidate gene with features typical of metalloproteases . This gene is located entirely within the most distal 1 . 5 kb of the chromosome . When introduced into virulent rice pathogens , the cloned gene specifically confers avirulence toward rice cultivars that contain Pi-ta . Frequent spontaneous loss of AVR-Pita appears to be the result of its telomeric location .
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Score: 3.00 |
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| | Journal: Biochem .
J Citation: V : 379 ( Pt 1 ) P : 125-31 | | Literature: oryza Field: abstract Doc ID: pub14692878 | | Abstract: The bglu1 cDNA for a beta-glucosidase cloned from rice ( Oryza sativa L ) seedlings was expressed as a soluble and active protein in Escherichia coli and designated BGlu1 .
This enzyme hydrolysed beta-1 , 4-linked oligosaccharides with increasing catalytic efficiency ( kcat/Km ) values as the DP ( degree of polymerization ) increased from 2 to 6 .
In contrast , hydrolysis of beta-1 , 3-linked oligosaccharides decreased from DP 2 to 3 , and polymers with a DP greater than 3 were not hydrolysed .
The enzyme also hydrolysed p -nitrophenyl beta-D-glycosides and some natural glucosides but with lower catalytic efficiency than beta-linked oligosaccharides .
Pyridoxine 5-O-beta-D-glucoside was the most efficiently hydrolysed natural glycoside tested .
BGlu1 also had high transglucosylation activity towards pyridoxine , producing pyridoxine 5-O-beta-D-glucopyranoside in the presence of the glucose donor p-nitrophenyl beta-D-glucoside . | Matching Sentences:
[ Sen. 1, subscore: 2.00 ]: The bglu1 cDNA for a beta-glucosidase cloned from rice ( Oryza sativa L ) seedlings was expressed as a soluble and active protein in Escherichia coli and designated BGlu1 . This enzyme hydrolysed beta-1 , 4-linked oligosaccharides with increasing catalytic efficiency ( kcat/Km ) values as the DP ( degree of polymerization ) increased from 2 to 6 . In contrast , hydrolysis of beta-1 , 3-linked oligosaccharides decreased from DP 2 to 3 , and polymers with a DP greater than 3 were not hydrolysed . The enzyme also hydrolysed p -nitrophenyl beta-D-glycosides and some natural glucosides but with lower catalytic efficiency than beta-linked oligosaccharides . Pyridoxine 5-O-beta-D-glucoside was the most efficiently hydrolysed natural glycoside tested .
[ Sen. 6, subscore: 1.00 ]: This enzyme hydrolysed beta-1 , 4-linked oligosaccharides with increasing catalytic efficiency ( kcat/Km ) values as the DP ( degree of polymerization ) increased from 2 to 6 . In contrast , hydrolysis of beta-1 , 3-linked oligosaccharides decreased from DP 2 to 3 , and polymers with a DP greater than 3 were not hydrolysed . The enzyme also hydrolysed p -nitrophenyl beta-D-glycosides and some natural glucosides but with lower catalytic efficiency than beta-linked oligosaccharides . Pyridoxine 5-O-beta-D-glucoside was the most efficiently hydrolysed natural glycoside tested . BGlu1 also had high transglucosylation activity towards pyridoxine , producing pyridoxine 5-O-beta-D-glucopyranoside in the presence of the glucose donor p-nitrophenyl beta-D-glucoside .
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Score: 4.00 |
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| | Journal: Acta Crystallograph . Sect . F Struct . Biol . Cryst Commun .
Citation: V : 62 ( Pt 8 ) P : 798-801 | | Literature: oryza Field: abstract Doc ID: pub16880561 | | Abstract: Rice ( Oryza sativa ) BGlu1 beta-glucosidase was expressed in Escherichia coli with N-terminal thioredoxin and hexahistidine tags and purified by immobilized metal-affinity chromatography ( IMAC ) .
After removal of the N-terminal tags , cation-exchange and S-200 gel-filtration chromatography yielded a 50 kDa BGlu1 with >95% purity .
The free enzyme and a complex with 2 , 4-dinitrophenyl-2-deoxy-2-fluoro-beta-D-glucopyranoside inhibitor were crystallized by microbatch and hanging-drop vapour diffusion .
Small tetragonal crystals of BGlu1 with and without inhibitor grew in 18% ( w/v ) PEG 8000 with 0 . 1 M sodium cacodylate pH 6 . 5 and 0 . 2 M zinc acetate .
Crystals of BGlu1 with inhibitor were streak-seeded into 23% ( w/v ) PEG MME 5000 , 0 . 2 M ammonium sulfate , 0 . 1 M MES pH 6 . 7 to yield larger crystals .
Crystals with and without inhibitor diffracted to 2 . 15 and 2 . 75 angstroms resolution , respectively , and had isomorphous orthorhombic unit cells belonging to space group P2 ( 1 ) 2 ( 1 ) 2 ( 1 ) . | Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: Rice ( Oryza sativa ) BGlu1 beta-glucosidase was expressed in Escherichia coli with N-terminal thioredoxin and hexahistidine tags and purified by immobilized metal-affinity chromatography ( IMAC ) . After removal of the N-terminal tags , cation-exchange and S-200 gel-filtration chromatography yielded a 50 kDa BGlu1 with >95% purity . The free enzyme and a complex with 2 , 4-dinitrophenyl-2-deoxy-2-fluoro-beta-D-glucopyranoside inhibitor were crystallized by microbatch and hanging-drop vapour diffusion . Small tetragonal crystals of BGlu1 with and without inhibitor grew in 18% ( w/v ) PEG 8000 with 0 . 1 M sodium cacodylate pH 6 . 5 and 0 . 2 M zinc acetate . Crystals of BGlu1 with inhibitor were streak-seeded into 23% ( w/v ) PEG MME 5000 , 0 . 2 M ammonium sulfate , 0 . 1 M MES pH 6 . 7 to yield larger crystals .
[ Sen. 2, subscore: 1.00 ]: Rice ( Oryza sativa ) BGlu1 beta-glucosidase was expressed in Escherichia coli with N-terminal thioredoxin and hexahistidine tags and purified by immobilized metal-affinity chromatography ( IMAC ) . After removal of the N-terminal tags , cation-exchange and S-200 gel-filtration chromatography yielded a 50 kDa BGlu1 with >95% purity . The free enzyme and a complex with 2 , 4-dinitrophenyl-2-deoxy-2-fluoro-beta-D-glucopyranoside inhibitor were crystallized by microbatch and hanging-drop vapour diffusion . Small tetragonal crystals of BGlu1 with and without inhibitor grew in 18% ( w/v ) PEG 8000 with 0 . 1 M sodium cacodylate pH 6 . 5 and 0 . 2 M zinc acetate . Crystals of BGlu1 with inhibitor were streak-seeded into 23% ( w/v ) PEG MME 5000 , 0 . 2 M ammonium sulfate , 0 . 1 M MES pH 6 . 7 to yield larger crystals . Crystals with and without inhibitor diffracted to 2 . 15 and 2 . 75 angstroms resolution , respectively , and had isomorphous orthorhombic unit cells belonging to space group P2 ( 1 ) 2 ( 1 ) 2 ( 1 ) .
[ Sen. 4, subscore: 1.00 ]: Rice ( Oryza sativa ) BGlu1 beta-glucosidase was expressed in Escherichia coli with N-terminal thioredoxin and hexahistidine tags and purified by immobilized metal-affinity chromatography ( IMAC ) . After removal of the N-terminal tags , cation-exchange and S-200 gel-filtration chromatography yielded a 50 kDa BGlu1 with >95% purity . The free enzyme and a complex with 2 , 4-dinitrophenyl-2-deoxy-2-fluoro-beta-D-glucopyranoside inhibitor were crystallized by microbatch and hanging-drop vapour diffusion . Small tetragonal crystals of BGlu1 with and without inhibitor grew in 18% ( w/v ) PEG 8000 with 0 . 1 M sodium cacodylate pH 6 . 5 and 0 . 2 M zinc acetate . Crystals of BGlu1 with inhibitor were streak-seeded into 23% ( w/v ) PEG MME 5000 , 0 . 2 M ammonium sulfate , 0 . 1 M MES pH 6 . 7 to yield larger crystals . Crystals with and without inhibitor diffracted to 2 . 15 and 2 . 75 angstroms resolution , respectively , and had isomorphous orthorhombic unit cells belonging to space group P2 ( 1 ) 2 ( 1 ) 2 ( 1 ) .
[ Sen. 5, subscore: 1.00 ]: Rice ( Oryza sativa ) BGlu1 beta-glucosidase was expressed in Escherichia coli with N-terminal thioredoxin and hexahistidine tags and purified by immobilized metal-affinity chromatography ( IMAC ) . After removal of the N-terminal tags , cation-exchange and S-200 gel-filtration chromatography yielded a 50 kDa BGlu1 with >95% purity . The free enzyme and a complex with 2 , 4-dinitrophenyl-2-deoxy-2-fluoro-beta-D-glucopyranoside inhibitor were crystallized by microbatch and hanging-drop vapour diffusion . Small tetragonal crystals of BGlu1 with and without inhibitor grew in 18% ( w/v ) PEG 8000 with 0 . 1 M sodium cacodylate pH 6 . 5 and 0 . 2 M zinc acetate . Crystals of BGlu1 with inhibitor were streak-seeded into 23% ( w/v ) PEG MME 5000 , 0 . 2 M ammonium sulfate , 0 . 1 M MES pH 6 . 7 to yield larger crystals . Crystals with and without inhibitor diffracted to 2 . 15 and 2 . 75 angstroms resolution , respectively , and had isomorphous orthorhombic unit cells belonging to space group P2 ( 1 ) 2 ( 1 ) 2 ( 1 ) .
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Score: 4.00 |
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| | Journal: Citation: V : ( ) P : | | Literature: oryza Field: abstract Doc ID: pub17405771 | | Abstract: Rice ( BGlu1 ) beta-glucosidase is a glycosyl hydrolase family 1 enzyme that acts as an exoglucanase on beta- ( 1 , 4 ) - and short beta- ( 1 , 3 ) -linked gluco-oligosaccharides .
Mutations of BGlu1 beta-glucosidase at glutamate residue 414 of its natural precursor destroyed the enzymes catalytic activity , but the enzyme could be rescued in the presence of the anionic nucleophiles formate and azide , which verifies that this residue is the catalytic nucleophile .
The catalytic activities of three candidate mutants , E414G , E414S , and E414A , in the presence of the nucleophiles were compared .
The E414G mutant had approximately 25 and 1400-fold higher catalytic efficiency than E414A and E414S , respectively .
All three mutants could catalyze the synthesis of mixed length oligosaccharides by transglucosylation , when alpha-glucosyl fluoride was used as donor and pNP-cellobioside as acceptor .
The E414G mutant gave the fastest transglucosylation rate , which was approximately 3 and 19 fold faster than E414S and E414A , respectively , and gave yields of up to 70-80 % insoluble products with a donor : acceptor ratio of 5 : 1 .
( 13 ) C-NMR , methylation analysis and electrospray ionization mass spectrometry showed that the insoluble products were beta- ( 1 , 4 ) -linked oligomers with a degree of polymerization ( DP ) of 5 to at least 11 .
The BGlu1 E414G glycosynthase was found to prefer longer chain length oligosaccharides that occupy at least three sugar residue binding subsites as acceptors for productive transglucosylation .
This is the first report of a beta-glucansynthase derived from an exoglycosidase that can produce long chain cello-oligosaccharides , which likely reflects the extended oligosaccharide binding site of rice BGlu1 beta-glucosidase .
| Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: Rice ( BGlu1 ) beta-glucosidase is a glycosyl hydrolase family 1 enzyme that acts as an exoglucanase on beta- ( 1 , 4 ) - and short beta- ( 1 , 3 ) -linked gluco-oligosaccharides . Mutations of BGlu1 beta-glucosidase at glutamate residue 414 of its natural precursor destroyed the enzymes catalytic activity , but the enzyme could be rescued in the presence of the anionic nucleophiles formate and azide , which verifies that this residue is the catalytic nucleophile . The catalytic activities of three candidate mutants , E414G , E414S , and E414A , in the presence of the nucleophiles were compared . The E414G mutant had approximately 25 and 1400-fold higher catalytic efficiency than E414A and E414S , respectively . All three mutants could catalyze the synthesis of mixed length oligosaccharides by transglucosylation , when alpha-glucosyl fluoride was used as donor and pNP-cellobioside as acceptor .
[ Sen. 2, subscore: 1.00 ]: Rice ( BGlu1 ) beta-glucosidase is a glycosyl hydrolase family 1 enzyme that acts as an exoglucanase on beta- ( 1 , 4 ) - and short beta- ( 1 , 3 ) -linked gluco-oligosaccharides . Mutations of BGlu1 beta-glucosidase at glutamate residue 414 of its natural precursor destroyed the enzymes catalytic activity , but the enzyme could be rescued in the presence of the anionic nucleophiles formate and azide , which verifies that this residue is the catalytic nucleophile . The catalytic activities of three candidate mutants , E414G , E414S , and E414A , in the presence of the nucleophiles were compared . The E414G mutant had approximately 25 and 1400-fold higher catalytic efficiency than E414A and E414S , respectively . All three mutants could catalyze the synthesis of mixed length oligosaccharides by transglucosylation , when alpha-glucosyl fluoride was used as donor and pNP-cellobioside as acceptor . The E414G mutant gave the fastest transglucosylation rate , which was approximately 3 and 19 fold faster than E414S and E414A , respectively , and gave yields of up to 70-80 % insoluble products with a donor : acceptor ratio of 5 : 1 .
[ Sen. 8, subscore: 1.00 ]: The E414G mutant had approximately 25 and 1400-fold higher catalytic efficiency than E414A and E414S , respectively . All three mutants could catalyze the synthesis of mixed length oligosaccharides by transglucosylation , when alpha-glucosyl fluoride was used as donor and pNP-cellobioside as acceptor . The E414G mutant gave the fastest transglucosylation rate , which was approximately 3 and 19 fold faster than E414S and E414A , respectively , and gave yields of up to 70-80 % insoluble products with a donor : acceptor ratio of 5 : 1 . ( 13 ) C-NMR , methylation analysis and electrospray ionization mass spectrometry showed that the insoluble products were beta- ( 1 , 4 ) -linked oligomers with a degree of polymerization ( DP ) of 5 to at least 11 . The BGlu1 E414G glycosynthase was found to prefer longer chain length oligosaccharides that occupy at least three sugar residue binding subsites as acceptors for productive transglucosylation . This is the first report of a beta-glucansynthase derived from an exoglycosidase that can produce long chain cello-oligosaccharides , which likely reflects the extended oligosaccharide binding site of rice BGlu1 beta-glucosidase .
[ Sen. 9, subscore: 1.00 ]: All three mutants could catalyze the synthesis of mixed length oligosaccharides by transglucosylation , when alpha-glucosyl fluoride was used as donor and pNP-cellobioside as acceptor . The E414G mutant gave the fastest transglucosylation rate , which was approximately 3 and 19 fold faster than E414S and E414A , respectively , and gave yields of up to 70-80 % insoluble products with a donor : acceptor ratio of 5 : 1 . ( 13 ) C-NMR , methylation analysis and electrospray ionization mass spectrometry showed that the insoluble products were beta- ( 1 , 4 ) -linked oligomers with a degree of polymerization ( DP ) of 5 to at least 11 . The BGlu1 E414G glycosynthase was found to prefer longer chain length oligosaccharides that occupy at least three sugar residue binding subsites as acceptors for productive transglucosylation . This is the first report of a beta-glucansynthase derived from an exoglycosidase that can produce long chain cello-oligosaccharides , which likely reflects the extended oligosaccharide binding site of rice BGlu1 beta-glucosidase .
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Score: 3.00 |
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| | Journal: J Mol Biol Citation: V : 377 P : 1200-15 | | Literature: oryza Field: abstract Doc ID: pub18308333 | | Abstract: The structures of rice BGlu1 beta-glucosidase , a plant beta-glucosidase active in hydrolyzing cell wall-derived oligosaccharides , and its covalent intermediate with 2-deoxy-2-fluoroglucoside have been solved at 2 . 2 A and 1 . 55 A resolution , respectively .
The structures were similar to the known structures of other glycosyl hydrolase family 1 ( GH1 ) beta-glucosidases , but showed several differences in the loops around the active site , which lead to an open active site with a narrow slot at the bottom , compatible with the hydrolysis of long beta-1 , 4-linked oligosaccharides .
Though this active site structure is somewhat similar to that of the Paenibacillus polymyxa beta-glucosidase B , which hydrolyzes similar oligosaccharides , molecular docking studies indicate that the residues interacting with the substrate beyond the conserved -1 site are completely different , reflecting the independent evolution of plant and microbial GH1 exo-beta-glucanase/beta-glucosidases .
The complex with the 2-fluoroglucoside included a glycerol molecule , which appears to be in a position to make a nucleophilic attack on the anomeric carbon in a transglycosylation reaction .
The coordination of the hydroxyl groups suggests that sugars are positioned as acceptors for transglycosylation by their interactions with E176 , the catalytic acid/base , and Y131 , which is conserved in barley BGQ60/beta-II beta-glucosidase , that has oligosaccharide hydrolysis and transglycosylation activity similar to rice BGlu1 .
As the rice and barley enzymes have different preferences for cellobiose and cellotriose , residues that appeared to interact with docked oligosaccharides were mutated to those of the barley enzyme to see if the relative activities of rice BGlu1 toward these substrates could be changed to those of BGQ60 .
Although no single residue appeared to be responsible for these differences , I179 , N190 and N245 did appear to interact with the substrates .
| Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: The structures of rice BGlu1 beta-glucosidase , a plant beta-glucosidase active in hydrolyzing cell wall-derived oligosaccharides , and its covalent intermediate with 2-deoxy-2-fluoroglucoside have been solved at 2 . 2 A and 1 . 55 A resolution , respectively . The structures were similar to the known structures of other glycosyl hydrolase family 1 ( GH1 ) beta-glucosidases , but showed several differences in the loops around the active site , which lead to an open active site with a narrow slot at the bottom , compatible with the hydrolysis of long beta-1 , 4-linked oligosaccharides . Though this active site structure is somewhat similar to that of the Paenibacillus polymyxa beta-glucosidase B , which hydrolyzes similar oligosaccharides , molecular docking studies indicate that the residues interacting with the substrate beyond the conserved -1 site are completely different , reflecting the independent evolution of plant and microbial GH1 exo-beta-glucanase/beta-glucosidases . The complex with the 2-fluoroglucoside included a glycerol molecule , which appears to be in a position to make a nucleophilic attack on the anomeric carbon in a transglycosylation reaction . The coordination of the hydroxyl groups suggests that sugars are positioned as acceptors for transglycosylation by their interactions with E176 , the catalytic acid/base , and Y131 , which is conserved in barley BGQ60/beta-II beta-glucosidase , that has oligosaccharide hydrolysis and transglycosylation activity similar to rice BGlu1 .
[ Sen. 5, subscore: 1.00 ]: The structures of rice BGlu1 beta-glucosidase , a plant beta-glucosidase active in hydrolyzing cell wall-derived oligosaccharides , and its covalent intermediate with 2-deoxy-2-fluoroglucoside have been solved at 2 . 2 A and 1 . 55 A resolution , respectively . The structures were similar to the known structures of other glycosyl hydrolase family 1 ( GH1 ) beta-glucosidases , but showed several differences in the loops around the active site , which lead to an open active site with a narrow slot at the bottom , compatible with the hydrolysis of long beta-1 , 4-linked oligosaccharides . Though this active site structure is somewhat similar to that of the Paenibacillus polymyxa beta-glucosidase B , which hydrolyzes similar oligosaccharides , molecular docking studies indicate that the residues interacting with the substrate beyond the conserved -1 site are completely different , reflecting the independent evolution of plant and microbial GH1 exo-beta-glucanase/beta-glucosidases . The complex with the 2-fluoroglucoside included a glycerol molecule , which appears to be in a position to make a nucleophilic attack on the anomeric carbon in a transglycosylation reaction . The coordination of the hydroxyl groups suggests that sugars are positioned as acceptors for transglycosylation by their interactions with E176 , the catalytic acid/base , and Y131 , which is conserved in barley BGQ60/beta-II beta-glucosidase , that has oligosaccharide hydrolysis and transglycosylation activity similar to rice BGlu1 . As the rice and barley enzymes have different preferences for cellobiose and cellotriose , residues that appeared to interact with docked oligosaccharides were mutated to those of the barley enzyme to see if the relative activities of rice BGlu1 toward these substrates could be changed to those of BGQ60 . Although no single residue appeared to be responsible for these differences , I179 , N190 and N245 did appear to interact with the substrates .
[ Sen. 6, subscore: 1.00 ]: The structures were similar to the known structures of other glycosyl hydrolase family 1 ( GH1 ) beta-glucosidases , but showed several differences in the loops around the active site , which lead to an open active site with a narrow slot at the bottom , compatible with the hydrolysis of long beta-1 , 4-linked oligosaccharides . Though this active site structure is somewhat similar to that of the Paenibacillus polymyxa beta-glucosidase B , which hydrolyzes similar oligosaccharides , molecular docking studies indicate that the residues interacting with the substrate beyond the conserved -1 site are completely different , reflecting the independent evolution of plant and microbial GH1 exo-beta-glucanase/beta-glucosidases . The complex with the 2-fluoroglucoside included a glycerol molecule , which appears to be in a position to make a nucleophilic attack on the anomeric carbon in a transglycosylation reaction . The coordination of the hydroxyl groups suggests that sugars are positioned as acceptors for transglycosylation by their interactions with E176 , the catalytic acid/base , and Y131 , which is conserved in barley BGQ60/beta-II beta-glucosidase , that has oligosaccharide hydrolysis and transglycosylation activity similar to rice BGlu1 . As the rice and barley enzymes have different preferences for cellobiose and cellotriose , residues that appeared to interact with docked oligosaccharides were mutated to those of the barley enzyme to see if the relative activities of rice BGlu1 toward these substrates could be changed to those of BGQ60 . Although no single residue appeared to be responsible for these differences , I179 , N190 and N245 did appear to interact with the substrates .
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